Automatic positive stop for rotating spindles



April 25, 1939. R. E. PRICE 2,155,681

AUTOMATIC POSITIVE STOP FOR ROTATING SPINDLES Filed Sept. 3, 1937 2 Sheets-Sheet l April 25, .1939.

R. E. PRICE AUTOMATIC POSITIVE STOP 1 03 ROTATING SPINDLES Filed Sept. 3, 1937 2 Sheets-Sheet 2 Snventor RALFH 15'. PRICE Patented Apr. 25, 1939 g UNITED STATES PATENT OFFICE AUTOMATIC POSITIVE STOP FOB ROTATING SPINDLES Ralph E; Price, Waynesboro, Pa., assignor to IAndis Tool Company, Waynesboro, Pa.

- Application September 3, 1937, Sel'ial No. 182,391

4 Claims. (Cl. 172-l'|9) My invention relates to an automatic stop stop. Said arm rotates about a pivot 23 in the a mechanism for stopping rotating parts positively belt guard II. The other end of said arm is in a predetermined position and it is an object of attached to a link 25 which is supported from same to provide electric and mechanical devices housing 24 by a bracket 20. A spring 21 one which will cooperate to'eflect the. desired result. end of which bears against said bracket and the s A further object is to provide means for renother end against a shoulder on link 26 urges said dering said stop mechanism operable only after link to the right and 'the stop i'l into contact the circuit to the headstock motor has been with cam II. Movement of saidlinkinthe oppoopened. 4 site direction is eflected by a solenoid 28 which A further object is to provide means for posiis secured to housing 24 by bracket 29. 10

tively preventing movement of the headstock The operation of my device is as follows: spindle beyond a predetermined point. The operator starts motor l3 by means of Previous brakes functioned either through elecswitch II. This energizes relay coil 36 and closes tric circuits such as by plugging or through sclethe circuits between feed lines I, 2 and l and i5 noids which operated friction type brake mechamotor ii. A circuit is also closed through lines nisms. These types of brakes are satisfactory if 81 and II to solenoid 28 which when energised the spindle is rotating at a slow speed. However, is effective to hold stop I! out of contact with at high speed suchbrakes permit a certain cam is. A normally closed circuit through line amount of drift which is necessary since it is I! through' normally closed time delay switch 40 I not desirable to stop a-rapidly rotating spindle to reverse relay coil ii is opened thus rendering too suddenly. My invention provides a means said relay inoperative. At the same time coil 42 for stopping, such high speed spindles positively which operates said switch II is deenergized perand accurately without being too abrupt. The mitting same to be closed by gravity. Since the motor is plugged when the switch is opened and supply to line a has been opened, closing switch a reversed through a revolution or less when a stop ll at this time has no effect. when it is desired shoulder engages a positive stop which was to stop the spindle, the operator opens switch 35 dropped into position when the motor was deenergizing coil 36 and cutting off the supply plugged. The reversing current through of current to motor II. The circuit through line resistances in order to keep down the torque of 31 is also broken at this time to deenergize solethe motor duringthe reverse movement and thus noid 28 and this; permit stop I! to be shifted reducethe shock of a positive stop. A dash pot into contact with cam is by means of spring 21. relay breaks the reverse circuit a predetermined Deenergizing e0 1 3 a so u s in closing a cirtime after the motor has been reversed and wit through line 39 and fl y closed Switch always after the reverse movement has been II .to coil II which reverses the supply of current stopped. to the armature and thus the direction of rota- 35 In the drawings Figure 1' is a front elevation tion of said armature. This reverse current of a headstock for a, grinding machine. passes through resistances "and II for the pur- Flgure 2 is a partial end elevation. pose of eiifecting the reverse movement at re- Figure 3 is a wiring diagram for the headstock duced torque thus reducing the shock of a posimotor. I tive stop. This reverse movement continues until 40 Numeral it, Figure 1, indicates a headstock shoulder ii on cam l5 engages stop I'I. Line 38 casting mounted 011 a Work table I n ro also supplies current to energize coil 42 to initiate :3 s p z i s :1 tig l by p g l movement of piston 45 in cylinder 40. After a s e I predetermined time depending on the adjustment 45 mounted on 110M118 The final drive of valve 41, said 'piston engages switch 40 and spindle is through a pulley I! mounted thereon. breaks the Mt to con deenemmng same A cam ll, secured to said pulley has a radial and mm the circuit to '3 face portion II which serves to engage a remov- I omnr, able positive stop l1 during a reverse movement r of said spindle. Said stop has a shank portion Mems ay? g; so is which is inserted in thehollow end of a piv- Predmmmed a m oted arm It. A spring II urges stop It driving said spindie, control means for said motor, wardly from arm is. A slot ii in said shank including a tart a d to wi means operapermits the insertion. of a pin 22 through the ble upon 0 8 said switch to start said motor 5 arm and shank to limit the movement of said and means operable upon opening said switch to u reverse said motor and a positive stop for stopping said reverse movement.

2. A driving mechanism for a spindle comprising a motor, control means for said motor including a start and stop switch, a stop on said spindle means for engaging said stop to positively stop rotation of said spindle, means operable upon closing said switch for withdrawing said stop engaging means from the path of said stop and for starting said motor, and means operable upon opening said switch for releasing said stop engaging means and for eifecting a reverse movement of said motor.

3. A driving mechanism for a spindle comprising a motor, control means for said motor including a start and stop switch, a stop on said spindle means for engaging said stop to positively stop rotation of said spindle, means operable upon closing said switch for withdrawing said' stop engaging means from thepath of said stop and for starting said motor, means operable upon opening said switch for releasing said stop engaging means and for eflecting a reverse movement of said motor, and means for eflecting said reverse movement at a lower torque than the forward movement.

4. A mechanism for stopping a rotating spindle comprising a motor for driving said spindle, a stop on said spindle, a stop engaging element normally in the path of said stop, a control mechanism for said motor including a starting switch, circuits operable upon closing said switch for moving said stop engaging means to inoperative position and for starting said motor, a normally closed circuit, a normally closed time delay switch in said circuit, means including said time delay switch for etl'ecting a reverse movement of said motor and means operable upon opening said starting switch for releasing said stop engaging means, stopping the flow of current to said motor and for closing the circuit through said time delay switch whereby to effect said reverse movement and after a predetermined time to open said reverse circuit.

RALPH E. PRICE. 

